function shows3()
{
		
	var Idiv=document.getElementById("Idiv3"); 
	Idiv.style.display="block";
	//以下部分要将弹出层居中显示
	Idiv.style.left=(document.documentElement.clientWidth-Idiv.clientWidth)/2+document.documentElement.scrollLeft+"px"; 
	Idiv.style.top=(document.documentElement.clientHeight-Idiv.clientHeight)/2+document.documentElement.scrollTop-30+"px";
	
	//以下部分使整个页面至灰不可点击
	var procbg = document.createElement("div"); //首先创建一个div
	procbg.setAttribute("id","mybg"); //定义该div的id
	procbg.style.background ="#000000";
	procbg.style.width ="100%";
	procbg.style.height ="100%";
	procbg.style.position ="fixed";
	procbg.style.top ="0";
	procbg.style.left ="0";
	procbg.style.zIndex ="90";
	procbg.style.opacity ="0.6";
	procbg.style.filter ="Alpha(opacity=70)";
	
	//以上部分也可以用csstext代替
	// procbg.style.cssText="background:#000000;width:100%;height:100%;position:fixed;top:0;left:0;zIndex:500;opacity:0.6;filter:Alpha(opacity=70);";
	//背景层加入页面
	document.body.appendChild(procbg);
	document.body.style.overflow ="hidden"; //取消滚动条
	
	
	//以下部分实现弹出层的拖拽效果
	var posX;
	var posY;
	Idiv.onmousedown=function(e)
	{
	if(!e) e = window.event; //IE
	posX = e.clientX - parseInt(Idiv.style.left);
	posY = e.clientY - parseInt(Idiv.style.top);
	document.onmousemove = mousemove; 
	}
	document.onmouseup =function()
	{
	document.onmousemove =null;
	}
	
	function mousemove(ev)
	{
		if(ev==null) ev = window.event;//IE
		Idiv.style.left = (ev.clientX - posX) +"px";
		Idiv.style.top = (ev.clientY - posY) +"px";
	}

} 


function closeDivs3() //关闭弹出层
{
	var Idiv=document.getElementById("Idiv3"); 
	Idiv.style.display="none";
	document.getElementById("mybg").style.display="none";
	document.body.style.overflow ="auto"; //恢复页面滚动条
	procbg=document.getElementById("mybg");
	procbg.parentNode.removeChild(procbg);
}
